[Outages-discussion] Internet "backbone"

[George Bonser]

> 
> > 2. I cannot stress this point enough especially if you have CTO/CIO
> > attendees: the Internet should not be used as a replacement for
> > dedicated circuits.  I can tell you factually that there are very
> > large, very important Fortune 500 companies who rely on the Internet
> > for transit of mission-critical applications/packets.  I cannot name
> > names (nor will I off-list -- the repercussions would be drastic),
> but
> > these companies "cannot justify the cost of dedicated circuits"[1].
> > Many seem to think that if you throw a VPN in front of something it
> > suddenly becomes reliable, only 3 months later do you find your
> > engineers on 3-hour-long bridges trying to explain what happened, the
> > concept of asymmetric routing, and how when you use the Internet for
> > transit you really are at the mercy of, well, everyone/everything.
> 
> Thanks for these excellent points Jeremy.
> 
> Re point 2, I remember trying to explain this exact point to medium
> sized organisations 12 years ago.

I deal with this even today.  People install a VPN over the internet and expect it to be reliable and waste hours of network engineering time troubleshooting intermittent issues when they can't be made to understand that the internet itself is intermittent.  And the asymmetrical routing needs to be absolutely driven home to people, particularly where one of the end points is multi-homed.  Packets may arrive via one transit provider having taken a path through one set of networks and the reply may return using the other provider and traverse a completely different set of networks on the way to the end point and there is no way to accurately discover that from only one end, it takes BOTH ends running a traceroute to each other to determine the path.

I have argued until I am blue in the face at various times and places that people should not use internet VPNs for mission critical services that are key to delivering the product.  But they don't listen.  People think the internet is magically resilient or something when, as mentioned in a different point, the only thing you can rely on is that the internet is broken SOMEWERE 24x7x365.  They just don't get it or they consider engineering time spent on these transient issues is somehow *free* (hey, they are paying the engineer anyway, right?).

Internet VPNs should be expected to work "most of the time" but they should not be expected to be all that reliable for 24x7x365 use.